In practice, the operational capability of devices is frequently conditional on their satisfactory attachment to a base body. For example, an airbag controller must be satisfactorily attached to the bodywork of a vehicle, or the vehicle body, if the airbag controller contains an acceleration sensor, where the sensor senses accelerations which act on the bodywork of a vehicle when a collision occurs. If the attachment is not satisfactory, an accident may not be satisfactorily detected so that the airbag is not properly triggered. There is also the risk of the airbag being inadvertently triggered if the controller is not carefully handled.